This invention relates generally to a liquid crystal display device and method of fabrication, and especially to a liquid crystal display device having improved contrast between white and black by including an anisotropic material between the polarizers of the device.
Super twisted nematic liquid crystal display devices, such as disclosed in Japan-Laid Open No. 60-50511, include a liquid crystal cell with electrode substrates having rubbing directions at an angle greater than 90.degree.. A pair of polarizers surround the cell with the polarizing axis (absorption axis) of each polarizer forming an angle between 30.degree. and 60.degree. relative to the rubbing direction of the adjacent substrate. The resulting birefringence causes white light passing through the device to be displayed as a green to reddish yellow color rather than white and as a bluish color rather than black when the device is turned off and on, respectively.
In summary, in a positive type display, white light tends to be displayed as green, yellowish green, yellow or reddish yellow when the device is turned off and blue or dark blue when the device is turned on. Similarly, white light passing through a negative type display device will be displayed as blue or dark blue when turned off and yellow when the device is turned on. In other words, prior art liquid crystal display devices are unable to display monochromatic black and white from white incident light. This inability is especially significant in the production of full color displays. Unfortunately, these prior art liquid crystal display devices also produce red and blue colored light with a lesser degree of brightness than green colored light resulting in unacceptable color performance.
Accordingly, it would be desirable to produce a liquid crystal display device which can overcome these problems associated with prior art devices.